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Special Publication No. 9015 

Brake o P eration and 
Manipulation in General 
Freight Service 

With a Review of Some of the 
Causes and Conditions Which Produce 
Shocks and Break-in-Twos 

BY 

W. V. TURNER 

n 

Being a Paper presented before the Chicago 
Railway Club—December Twenty-first, 1909 



j ) ) 

THE WEST1NGHOUSE AIR BRAKE COMPANY 
PITTSBURGH, PENNSYLVANIA 
April, 1910 







0 




COPYRIGHT, 1910 
BY 

THE WESTINGHOUSE AIR BRAKE CO. 



©CI.A261898 


0 

\ 

\ 

\ 


BRAKE MANIPULATION AND OPERATION IN GENERAL 
FREIGHT SERVICE, WITH A REVIEW OF SOME 
OF THE CAUSES AND CONDITIONS WHICH 
PRODUCE SHOCKS AND BREAK- 
IN-TWOS. 


In the design of any brake equipment the starting point is al¬ 
ways the weight of the vehicle to which the brake is to be applied, 
Given the weight of the vehicle, the problem then reduces simply 
to choosing the proper size brake cylinder which, with a predeter¬ 
mined maximum brake cylinder pressure and leverage ratio will 
give the desired percentage of braking power. The process is 
clearly a simple one when applied to any given car and the method 
of procedure applied to cars of various weights will insure uni¬ 
formity of results. However, it must necessarily follow that a 
brake equipment designed in this way for one car will not be proper 
for another car of a different weight from the first. The greater 
the difference in the weights of the cars, the greater will be the 
difference in the equipments required. 

Underlying this proposition are fixed principles to which we 
must work if the best results are to be obtained, and once a set is 
determined upon for any design they must be continued as uni¬ 
formity as fundamentally important. Of course, it must not be 
understood that departures from a -proper basis will render a de¬ 
sign inoperative, but it will not be as good as it should be in in¬ 
creasing proportions as it departs from the true starting point. 

First: The thing to be fixed upon is the percentage of braking 
power permissible. 

Second: The pressure to be used as a power base. 

Third: Either the leverage or the size of the brake cylinder to 
be used. 

(If the size of cylinder is determined upon, this will fix the lever¬ 
age; if the leverage is determined upon, this will fix the size of 
cylinder). 


4 


Brakes in Freight Service 


Regarding the first consideration, namely, percentage of braking 
power, experience has confirmed that 70 per cent, of the light 
weight of car on 60 pounds cylinder pressure (60 per cent, on 50 
pounds cylinder pressure) is the practically perfect basis for a 
freight car, and for reasons that are too obvious to require state¬ 
ment; but it should be added that reason confirms the experience. 

Regarding the second: This is important in two respects 
1st, that it must be an obtainable pressure, 2nd, that it is univer¬ 
sally applicable and adopted. 

Regarding the third: This resolves itself into the question of 
how many times the cylinder power can be multiplied in a prac¬ 
tical way, and is determined by the possible “lost motion” of the 
car, and the permissible increase of piston travel due to shoe wear, 
as the greater the number of times the cylinder value is multi¬ 
plied, the more quickly will shoe wear lengthen the travel of the 
brake piston. 

With the exception of the strength of materials, no other factors 
enter into the design, but those cited are vital and must be con¬ 
sidered, and cannot be slurred over, nor can any one of them be 
omitted from the consideration and allowed to fix itself, for all 
others are so intimately related that they may be termed the one 
law of brake design. 

It is often thought that an increase or decrease of the brake 
pipe pressure carried affects the design, but this is not the case, 
as this will only increase or decrease the braking power in an exact 
ratio to the change of pressure. 

Assuming that sound principles and good judgment have been 
employed in designing the fixed apparatus of an air brake, namely, 
the triple valve, reservoirs, brake cylinder, etc., and that these 
operate perfectly as individual units, and particularly in the la¬ 
boratory where no moving vehicles are to be considered and, con¬ 
sequently, neither variations in power developed in the different 
cylinders, nor difference in time complicate the results of manip¬ 
ulation. It is necessary before discussing the actual manipula¬ 
tion of the brake to point out some of the factors which affect the 
operation and the manipulation of the brakes on the train as a 
whole. These may so change the original design as to make smooth 
manipulation and operation impossible. It appears to be thought 
by many that the brake being automatic in its action should also 


Brakes in Freight Service 


5 


be automatic in compensating for any lack of knowledge or for 
neglect on the part of those who use it, but this is not the case, 
and is as impossible of accomplishment as to run a locomotive with¬ 
out steam. The operation of the brake is according to fixed laws 
and conditions over which the engineer of all men has the least control. 

As an elaboration of the principal factors involved would take 
up more time than has been at my disposal since being called upon 
to give this paper and, undoubtedly, more than is at our disposal 
this evening, I cannot do more than state them and summarize the 
effects. 


PERCENTAGE OF BRAKING. 


First: The percentage of braking power, so called. This has 
usually been figured at 70 per cent, on the light weight of the car, 
and this is certainly sufficient for the car when empty, but mani¬ 
festly is reduced for the load in ratio to the difference in the weight 
of the car when empty and the car and load together. For example: 
If the braking power of a 40,000 pound car of 100,000 lbs. capa¬ 
city is 70 per cent, when empty, it will be less than 19 per cent, 
when loaded. 


PRESSURE. 


Second: The cylinder pressure obtained in the designs. This 
is supposed to be uniform for any given reduction and if the proper 
cylinder volume is maintained, it will be approximately so, 
but if the cylinder volume varies on the different vehicles, the 
pressure obtained will correspondingly vary, being less than nor¬ 
mal for increase of volume and greater than normal for decrease 
of volume. Moreover, it is intended in the design that a low cyl¬ 
inder pressure be obtained for light reductions and a high cylinder 
pressure for heavy reductions, and this is the natural result, but 
lack of maintenance often brings about the opposite to this, for 
if the cylinder volume is small, a very high pressure will be ob¬ 
tained with a comparatively light reduction, while a low cylinder 
pressure will be obtained for a heavy one, and to avoid the results 
contingent upon this requires a knowledge of conditions and the 
exercise of a judgment possessed only by the few. 


6 


Brakes in Freight Service 


PISTON TRAVEL. 

Third: Piston travel is such a factor in brake operation that 
its variation varies every operation of the brake as far as the devel¬ 
oping power is concerned, for not only is the piston travel respon¬ 
sible for the variation in the cylinder pressure pointed out above, 
but it also varies the time required to obtain the braking power 
expected to be developed from a given brake pipe reduction. 
In other words, it is possible to obtain several times the braking 
power on one car as compared with another, due only to variation 
in piston travel, and it does not require a very vivid imagination 
to picture what this means to brake manipulation as far as pro¬ 
ducing shocks are concerned and it will also be seen that this is a 
factor over which the engineer has absolutely no control. More¬ 
over, this variation in piston travel may be such as to entirely 
change the percentage of braking power expected to be obtained 
from the design for a given reduction, thus causing excessive 
braking power on some cars and too little on others, which is both 
prolific of shocks, due to surging, and of flat wheels, due to cars 
being dragged or bumped “off their feet.” 

TIME. 

Fourth: The time element is a very serious factor as affecting 
both the application and release of the brakes. In applying the 
brakes the starting takes place very quickly throughout a short 
train, therefore, there is no running in or out of slack and, conse¬ 
quently, little or no shock, but in the long train, there is a con¬ 
siderable interval of time between the starting of the brakes on the 
head end and rear end of the train. In fact, the brakes on the head 
end may have fully applied for the reduction before they commence 
to apply on the rear end of the train, and unless great care and judg¬ 
ment is exercised to prevent bunching of the train, very serious 
results are likely to occur when the brakes apply at the rear and the 
reaction of the draft gear can stretch the train. Again, the rise of 
cylinder pressure is very different in the long train than in a short 
one, for the cylinder pressure cannot rise at any greater rate than 
the brake pipe pressure is being reduced and as this varies with 
the length of train, particularly at the rear end, it will be seen 
that the time factor must be considered with every brake mani¬ 
pulation. 


Brakes in Freight Service 


7 


The difference in and effect of time as affecting brake applica¬ 
tions are graphically illustrated on Slides 824, 825, 707, 709, 711, 
713, 642, 643, 644 and 645 of the Appendix, in which also some of 
the characteristics of the curves are pointed out. 

As to the release of the brakes, the time element also must be 
taken into account, for, obviously, there must be an interval of 
time between the release of the brakes at the head and rear end. 
This is certain even where the reduction has not been made below 
the equalizing point, but when the equalizing point has been passed, 
this difference is increased to such an extent that the engineer 
very often opens the throttle and accelerates the head end of the 
train while retardation is still taking place at the rear, and this 
even after he has thought he had allowed time enough. If it is 
important that the train be stretched before brakes are applied, 
it is doubly so before the brakes are released. 

The difference in and effect of time as affecting the release of the 
brakes are graphically illustrated on Slides 598, 708, 710, 712 and 
714 of the Appendix, in which also some of the characteristics of 
the curves are pointed out. 

LOADS AND EMPTIES. 

Fifth: Perhaps the most serious factor involved in freight 
train control is that arising from hauling loads and empties mixed, 
and this without considering any of the other factors enumerated 
above, but when considered in conjunction with them, the situa¬ 
tion is certainly more serious than most people seem to think. As 
was pointed out, the braking power varies inversely, as the load 
and as the cars are now designed to carry about three times their 
weight, it will be seen that while the brake shoe pressure remains 
the same as for the light car the percentage of braking power, so 
called, to weight, has been reduced to one-fourth of what it was or 
is on the light car. If now we consider what must be the result 
of difference in cylinder pressure obtained and the time in which 
it is obtained on the empty and loaded car, it will be seen that 
with the present equipment, the only salvation against shocks and 
break-in-twos is (1st) to keep the train stretched—(2nd) to make 
at least initial reduction light in order that only a low power will 
be developed until the slack has adjusted itself—and (3rd) under 


8 


Brakes in Freight Service 


no circumstance to release the brakes, unless the slack condition 
of the train permits, until a stop be made. The usual custom is to 
haul the loads ahead and the empties behind and this is certainly 
more proper than hauling the empties ahead and the loads behind, 
for in case of a shock, with the empties behind, the result is at 
worst a parting of the train, while with the loads behind, the re¬ 
sult is a buckling, which will be disastrous, particularly on par¬ 
allel track roads. A better method of hauling loads and empties 
in the same train is to alternate them; thus avoiding great differ¬ 
ences of braking power, due to variation in weight of train at any 
section of the train. This, however, involves switching, etc., which 
renders such a method impracticable. A better method still is to 
haul loads and empties in different trains. This again is im¬ 
practicable on many roads. Thus, the proposition reduces to one 
of proper inspection and maintenance, instruction and discipline, 
which involves considerable intelligence and experience, or failing 
this, the proposition reduces to a cheerful acceptance of the conse¬ 
quences. 

For a graphical illustration of conditions existing by reason of 
loads and empties, long and short piston travel and differences in 
“braking power” designs, Slide 774 of the Appendix. 

It will be seen that all these factors are so intimately related 
that one involves the other to a considerable degree with the pos¬ 
sible exception of loads and empties. Therefore, any neglect of 
one affects the other and conversely any great thought or consider¬ 
ation of the one improves the other. This relationship existing and 
time being limited, it will probably serve the purpose to consider 
two of these factors only at greater length, namely, 

First: As to piston travel. 

Second: As to braking power most desirable for freight cars 
under present operating conditions. 

PISTON TRAVEL. 

Piston travel may be divided into theoretical (under certain con¬ 
ditions Standing Travel closely approximates the theoretical travel) 
and actual travel (as under running conditions the travel differs 
from that obtained when the vehicle is standing). The theoretical 
travel is that which the brake cylinder piston is allowed to move in 
order to give proper shoe clearance, plus the movement due to the 


Brakes in Freight Service 


9 


necessary difference between the diameter of the pins and holes. 
Thus the theoretical travel equals the shoe clearance times the total 
leverage plus the travel due to difference in the diameter of the pins 
and holes. 

The actual travel is comprised of the above plus that resulting 
from lost motion due to loose fitting brasses, play between boxes 
and pedestals, brake beam deflection and unusual temporary 
strains; in fact, to anything that produces or increases lost motion. 
I wish particularly to call attention to the practice of hanging brake 
beams from what amounts to a spring suspension, that is, to the 
car body or the truck frame above the springs. In such cases the 
shoes are drawn toward the rail by the pull of the wheel with conse¬ 
quent lengthening of piston travel. This is a most serious evil 
and where it exists the piston travel must be quite frequently ad¬ 
justed to compensate for shoe wear, or the brake piston will strike 
the cylinder head; and in any case where excessive “false” travel is 
likely to develop a very low ratio of leverage should be employed. 

The difference between the actual and the theoretical travel is 
erroneously called “false” travel, which, serious as it is, receives 
less consideration than any other thing in car design. 

The theoretical piston travel is commonly called Standing Travel, 
and is defined as the distance the brake cylinder piston is forced out¬ 
ward in applying the brakes when the car is not in motion. 

The actual piston travel is generally called the Running Travel 
and is defined as the distance the brake cylinder piston travels out¬ 
ward in applying the brakes when the car is in motion. 

In studying the effects of piston travel, it must be remembered 
that in any application of the brakes, the brake cylinder pressure 
obtained depends upon two things; the ratio between the volumes 
of the cylinder and auxiliary reservoir, and the amount of brake 
pipe reduction. If the brake pipe pressure is reduced 10 pounds, 
the auxiliary reservoir will be reduced 10 pounds (slightly over); 
and the 10 pounds from the auxiliary reservoir going into the 
brake cylinder will create there a pressure depending on the vol¬ 
ume of the cylinder and connecting passages as compared with 
that of the auxiliary reservoir. But the auxiliary reservoir vol¬ 
ume does not change, so we may say that of the two, the brake 
cylinder volume alone is responsible for the pressure obtained. 
Now that volume depends on the amount of piston travel, if the 


10 


Brakes in Freight Service 


latter is short, the volume is small, and the 10 pounds auxiliary 
reservoir air will create a higher brake cylinder pressure than if 
the piston travel was longer and the cylinder volume thereby 
greater. 

In order to show what a great difference the variation of piston 
travel makes in brake cylinder pressure and braking power, we 
show on Slides 853 and 854 curves showing the theoretical variation 
for an 8-inch by 12-inch freight cylinder with standard cast iron 
auxiliary reservoir, with 6-inch, 8-inch and 10-inch piston travel, 
for different brake pipe reductions. Slide 853 shows the relative 
increase or decrease of cylinder pressure as piston travel is decreased 
or increased. For example, with a 6-inch piston travel a 10 lb. re¬ 
duction gives 34 lbs. cylinder pressure; while, with 8 inch 23 lbs., 
and for 10 inch 16 lbs. is obtained. Difference enough, it will be 
seen, to make those concerned take notice. Slide 854 gives the per¬ 
centage that the results in braking power obtained with the 6-inch 
piston travel are greater than those with the 8-inch travel; also the 
percentage less resulting with 10-inch travel as compared with 
the 8-inch travel. These curves show what great and damaging 
variations of cylinder pressure and braking power result with the 
initial brake pipe reductions. For example, with a 10-pound re¬ 
duction, the braking power developed with a 6-inch travel is 45 
per cent, greater than with an 8-inch travel; also a 10-inch travel 
gives 38 per cent, less than an 8-inch travel. In practice, the cyl¬ 
inder pressures realized are two or three pounds less than shown on 
the curves, while the braking power is considerably less, due to the 
lost motion, friction, and elasticity of the foundation brake gear. 
These losses make the conditions even worse than shown on Slide 
854. 

We give in Table 1 the results that would be obtained in service 
with a 10-pound brake pipe reduction were there no losses of any 
kind. As a matter of fact the results actually obtained in service 
will be from two to three pounds lower, on account of leakage, etc. 
The effective braking power is that which would be delivered at the 
brake shoes for the cylinder pressure given, assuming that the 
leverage is designed for 60 per cent, braking power at 50 pounds 
pressure, this percentage being now recommended in freight ser¬ 
vice for steel cars, or wooden cars with steel underframes. In 
practice, 8-inch piston travel is usually taken as standard for 
freight service. 


Brakes in Freight Service 


11 


Table 1. 


Piston 

Cylinder 

Effective Braking 

Comparison with 

Travel 

Pressure 

Power 

8-inch Travel 

4" 

52^ lbs. 

63 % 

130 greater 

5" 

41 lbs. 

49 % 

78 “ 

* 6" 

33 lbs. 

39i% 

44 “ 

7" 

27i lbs. 

33 % 

20 “ 

* 8" 

23 lbs. 

27i% 

— 

9" 

19 lbs. 

23 % 

16^ less 

*10" 

16 lbs. 

19 % 

31 “ 

11" 

13 lbs. 

15i% 

44 “ 

12" 

11 lbs. 

13 % 

53 “ 


*See Slides 853 and 854. 


Brake cylinder pressure and braking power developed with an 
8-inch by 12-inch cylinder, having 50 cu. in. clearance, and stand¬ 
ard cast-iron auxiliary reservoir, with a 10-pound brake pipe re¬ 
duction, and different piston travel, no losses whatever being con¬ 
sidered, nominal braking power being 60 per cent, on 50 lbs. cylin¬ 
der pressure. 

Tables similar to this could be made for any other brake pipe 
reduction, showing a variation similar in character but different 
in amount, the latter being greatest for small brake pipe reduc¬ 
tions. As a result, it will be readily seen that if in a train, some 
brake cylinders have long piston travel and some short, a very 
uneven braking power will be developed for any brake pipe re¬ 
duction, which will cause some cars to be retarded more than 
others, from which shocks and unnecessary strains on draw bars 
will result. 

The proper piston travel is that which will develop approxi¬ 
mately 50 pounds cylinder pressure when the auxiliary reservoir 
and brake cylinder become equalized from an initial auxiliary re¬ 
servoir pressure of 70 pounds. This cylinder pressure (50 pounds) 
will then be the limit for a full service application, and should be 
obtained simultaneously on all cars. In Table 2 we show ap¬ 
proximately the pressures at which the cylinder and auxiliary 
reservoir above mentioned will become equalized for different pis¬ 
ton travels, and the brake pipe reduction required to give these 
equalizations. 




12 


Brakes in Freight Service 


Table 2. 

Equalization pressures and brake pipe reductions necessary to 
give them for the brake cylinder and auxiliary reservoir given in 
Table 1, with initial auxiliary reservoir pressure of 70 lbs. and dif¬ 
ferent piston travel. 


8 -Inch by 12-Inch Cylinder and Cast Iron Auxiliary Reservoir 


Piston Travel 

Equalization Pressure 

Brake Pipe Reduction 

4" 

59 lbs. 

11 lbs. 

5" 

57 lbs. 

13 lbs. 

* e" 

55 lbs. 

15 lbs. 

7" 

534 lbs. 

164 lbs. 

* 8" 

514 lbs. 

184 lbs. 

9" 

50 lbs. 

20 lbs. 

*10" 

49 lbs. 

214 lbs. 

11" 

47 lbs. 

23 lbs. 

12" 

46 lbs. 

24 lbs. 


*See Slides 853 and 854. 


Particular attention should be given, in this table, to the large 
variation in brake pipe reductions, the short piston travels requir¬ 
ing a smaller reduction and equalizing at a higher pressure than 
in the case of longer travels. To illustrate the detrimental effects 
of having such conditions in a train, let us suppose that two freight 
cars are coupled together, each having a light weight of 35,000 
pounds, each equipped with an 8-inch cylinder and cast-iron 
auxiliary reservoir, and the first having a piston travel of 11 inches 
and the second of 5 inches. It is plain that if a full service appli¬ 
cation is required on these two cars, a brake pipe reduction of 
sufficient amount must be made to equalize brake cylinder and 
auxiliary reservoir on both cars, which in this case would be 23 
pounds, although 13 pounds would be sufficient for the second 
car. Consequently, 10 pounds of brake pipe air is wasted from 
the second car, and it obtains a cylinder pressure of 57 pounds, 
while the first car only obtains 47 pounds; moreover, the higher 
pressure on the second car is obtained in less than six-tenths of 
the time that the lower pressure is obtained on the first car. That 
is, there was 57 lbs. in the brake cylinder of the first car mentioned 
at the time that only 20 lbs. was in the cylinder of the second car. 




Brakes in Freight Service 


13 


Let us suppose these two cars to be arranged to deliver 60 per 
cent, of braking power with 50 pounds cylinder pressure; then 
57 pounds represents 68-j- per cent, braking power, and 47 pounds 
represents 56J. 68^ per cent, of 35,000 pounds is 24,000, and 

56-j- per cent, is 20,000 pounds. As a result, the stopping power 
of the second car is 4,000 pounds greater than on the first, and 
a draw-bar pull of this amount is maintained between the two 
cars throughout the stop, or until the release of the brakes. If 
the release is made before coming to a stop, the brake pipe pres¬ 
sure need only be raised about 1^ pounds to cause the first car 
brakes to start to release, while it must be raised about 12 pounds 
before the second car brakes start to release. The first car, having a 
comparatively low cylinder pressure, would probably fully release 
before the second car started to, resulting in a draw-bar pull for a 
short time equal to the entire braking power of the second car, 
which, in this case, is 24,000 pounds. This belated release is often, 
but incorrectly, called “a slow release;” while that on the first car 
would be termed “a quick release”; as a matter of fact, if the two 
cylinders started to release at the same time from the same pres¬ 
sure, they would take an equal time to accomplish it. The fault 
lies, not in the brake apparatus, but in the improper adjustment 
of the foundation brake gear. 

But still another condition might arise. Suppose a 14-pound 
brake pipe reduction should be made; the second car would equal¬ 
ize at 57 pounds, or 68 \ per cent—24,000 lbs. braking power, 
while the first car would only have a cylinder pressure of 24 pounds, 
the latter representing 29 per cent, braking power, or 10,000 
pounds retarding effect. In this case, the draw-bar pull between 
the two cars during the application is 13,900 pounds, and amount 
over six times as much as would be necessary for the first car to 
bring the second, the-latter loaded with 100,000 pounds of freight 
from a standstill to 20 miles per hour in one minute. 

From these considerations, it is clear that the best operation 
of the brakes can only be secured by maintaining a uniform piston 
travel upon all cars. The increase in the slack of brake rigging 
due to the wearing away of the brake shoes, must be constantly 
watched and taken up by means provided in the brake rigging, 
thereby maintaining the piston travel as nearly uniform as pos¬ 
sible. By far the best means for accomplishing this is to install, 
in all cases where possible, an automatic slack adjuster, so called. 


14 


Brakes in Freight Service 


Where this is not done, proper inspection and adjustment must 
be made at sufficiently frequent intervals to prevent any material 
increase in piston travel. As this inspection and adjustment has 
to be made while the car or train is standing, it must be remem¬ 
bered that running travel in steam road service is generally about 
1J inches to 2 inches longer than standing travel, so that if an 8-inch 
running travel is desired, the standing travel should be adjusted 
to about 6 inches. If slack adjuster (shoe wear compensator) 
is used, attachment should be made to the 8-inch hole in cylinder. 

Piston travel should never be altered to obtain a certain shoe 
clearance. This should be done by using brake cylinder of proper 
size, and through proper proportioning of the foundation brake 
gear. When inserting new shoes to replace those worn out, the 
brake rigging should be slacked off first, and the piston travel 
adjusted properly after the new shoes are in place. If, for any 
reason, it becomes necessary to change the piston travel, the auxil¬ 
iary reservoir must also be changed, so as to keep the relative vol¬ 
umes of brake cylinder and auxiliary reservoir the same as before, 
thus insuring the same equalizing pressure and corresponding 
pressures for given brake pipe reductions. 

The question as to whether the piston travel should be adjusted 
when the car is light or loaded makes necessary the following state¬ 
ment : Whenever the brake beam hangers are suspended from the 
solid part of the truck (which is now the best and most general 
practice), it is immaterial whether the car is light or loaded. If 
the hangers are attached to the car body, the adjustment must 
be changed whenever the car goes from light to load, or vice versa, 
for the following reasons: If the adjustment is done when the 
car is loaded, full braking power is available when the greatest 
weight is being handled, while there is a possibility, when the 
car is light and the shoes are raised making the shoe clearance 
less, that the resulting decrease in piston travel may raise the 
cylinder pressure sufficiently to slide the wheels. On the other 
hand, if the adjustment is made when the car is light, and the 
shoes in their uppermost position, wheel sliding is avoided, but 
there is danger that, when loaded, the increase of shoe clearance 
and piston travel may result in greatly reducing the efficiency of 
the brake, and possibly no braking power at all for light deduc¬ 
tions, which condition might cause runaways and disaster. 


Brakes in Freight Service 


15 


It is clear that a uniform piston travel is most desirable. If 
the piston travel be unnecessarily long, the brake cylinder pres¬ 
sure is thereby reduced and the efficiency of the brakes corre¬ 
spondingly impaired; in addition, a greater quantity of com¬ 
pressed air is consumed in brake applications than would other¬ 
wise be necessary, thereby entailing greater demands upon the 
air compressor, with correspondingly increased wear and tear. 
If the piston travel be too short, it is apt to be accompanied by 
dragging of the brake shoes upon the wheels while the brakes 
are released, and by too high a brake cylinder pressure, with an 
accompanying liability of sliding wheels, and rough and sudden 
stops when the brakes are applied. Besides, with a constantly 
varying piston travel, the engineer is never sure what retarding 
effect will follow any certain brake pipe reduction, and he will 
lose confidence in the brake; he can not become as expert in its 
manipulation as if the operation was more uniform, which if proper 
installation has been made, becomes largely a question of piston 
travel. 

Curves illustrating the foregoing are given on Slides 254, 852, 853 
and 854 of the Appendix, as well as a brief explanation of some of 
the characteristics. 


BRAKING POWER. 

When the Automatic Air Brake was being put to a practical appli¬ 
cation, that is, used for controlling trains, it was found that the 
amount of cylinder pressure and braking power obtained for a 
given reduction were very important factors to be considered. 
After considerable experience it was proven, even for the com¬ 
paratively short trains of those days, that the highest permissible 
braking power should not greatly exceed 1 per cent, per pound of 
cylinder pressure (e. g., 70 per cent, on 60 lbs. cylinder pressure) 
if trains were to be handled without shocks in ordinary service 
operation, and also that the cylinder pressures obtained should not 
exceed 3J lbs. absolute, per pound of brake pipe reduction; in 
other words, the auxiliary reservoir and brake cylinder should 
equalize at 50 lbs. from 70 lbs. initial; gage pressures (65 lbs. 
minus 15 for piston displacement). Accordingly a nominal brak¬ 
ing power of something less than 60 per cent, on 50 lbs. cylinder 
pressure was fixed upon as the proper braking power for freight 


16 


Brakes in Freight Service 


cars and an auxiliary reservoir employed so proportioned as to give 
a proper brake cylinder pressure per pound of brake pipe or auxil¬ 
iary reservoir reduction and a brake pipe pressure of 70 lbs. was 
fixed upon as the desired pressure from which to obtain the maxi¬ 
mum service brake cylinder pressure, namely, 50 lbs. These 
principles, of course, implied that “all air” trains were being 
handled for the reason that the length of train is an important 
factor in producing shocks, as if only a few air brake cars were 
being used, the brakes could not be much of a factor in stretching 
the train. However, it became the custom to use only a number 
of the brakes in long trains, generally on the loads ahead, the 
brakes on the empties not being used. Therefore, it was largely 
immaterial, under this condition of operation, what nominal brak¬ 
ing power was adopted for the empty cars, as, obviously, if the 
brakes were not used, they could not stretch the train when being 
hauled behind loads. It was during this period that some roads 
increased the braking powers of freight cars from 70 to as high 
as 85 per cent, based on 60 lbs. cylinder pressure, and, of course, 
the result when hauling empties behind loads, particularly on a 
level, did not manifest itself as they were generally behind the 
cars on which the brakes were being used. When, however, it be¬ 
came the rule to operate “all air trains” quite another set of con¬ 
ditions were created, for not only were the brakes used on empties 
but, as far as the operation of the brakes was concerned, the length 
of trains was doubled, which is a serious factor, as the interval of 
time in brake application, particularly when combined with great 
difference of braking power at the two ends of the train, permits of 
the slack actions that are responsible for shocks. Thus the brak¬ 
ing power of the empty cars became quite a factor in the handling 
of trains, for, obviously, the greater the braking power of the 
empties as compared with the load for the same cylinder-pressure 
obtained from the medium reduction, the greater would be the re¬ 
tardation of the empties over the loads with consequent shocks and 
possible break-in-twos, particularly if the slack was bunched when 
the brakes were applied. Because of these things, a return was 
made to the old rule of 60 per cent, nominal braking power based 
on 50 lbs. cylinder pressure, and even this would be regarded as 
too high, if means were available for properly taking care of the car 
when loaded. If the braking power is made very great on the empty 
cars an approach- will be made to the bad practice which was re- 


Brakes in Freight Service 


17 


sponsible for so many break-in-twos when employed, namely, haul¬ 
ing passenger cars with the brakes in use on the rear end of a freight 
train, or, what is perhaps even worse, permitting empty freight cars 
with short piston travel to be hauled behind loads. 

Another thing that should be kept in mind is that a vital ele¬ 
ment in handling long trains without shock is the uniformity of 
the braking power both in time and amount, and as there is no 
such thing as uniformity in the amount of braking power when we 
consider loaded and empty cars with long and short piston travel 
and the various percentages of nominal braking power employed, 
etc., nor of time when we consider that this is varied by length of 
train and brake pipe leaks, etc., it is important that we prevent the 
ill effects of these variations to as great a degree as possible, which 
can best be done by insuring that the braking power obtained be as 
low as controlling the loaded car will permit, and its attainment 
stretched over such a period of time by range of brake pipe reduc¬ 
tion, as will make sudden and severe strains unlikely. This is not 
only desirable but possible from the fact that all the braking power 
needed for controlling'the loaded cars, even on grades, can be ob¬ 
tained by increasing the brake pipe pressure, which increases the 
ultimate braking power on all cars alike and without in any way 
interfering with the flexibility of the brake, i. e., without giving 
severe braking power for the initial brake pipe reduction, which it 
is important to avoid until the slack has had time to adjust itself. 
Moreover, this increase of brake pipe pressure does not widen the 
gap, already too great, between the ordinary service braking effort 
of the loaded and empty cars, while to increase the braking power 
on the empty cars does this to a serious degree. In other words, 
it does exactly opposite to what good .engineering requires and 
what we are endeavoring to do, namely, bring about a uniformity 
of braking power on the empty and loaded cars. 

In this connection, we might also mention that when it was 
found necessary to increase the stopping power of passenger trains, 
it was not done by increasing percentage of braking power per 
pound of cylinder pressure, which, to obtain the increase desired, 
would have destroyed the flexibility of service features of the brake, 
but,by increasing the pressure carried, thereby obtaining a cylinder 
pressure sufficiently high to give the desired increase of braking 
power. If this was the necessary procedure with passenger trains, 


18 


Brakes in Freight Service 


how much more so with the long freight trains where the time and 
slack elements are of a much more variable and serious nature. 

To compare the relative gain on empty and loaded cars by the 
proposed increase in nominal percentage of braking power (and 
considering service operation only, as the question of uniformity 
mentioned above need not be considered in emergency) we may 
take the following example: 


PRESENT STANDARD. PROPOSED STANDARD. 

70% on 60 lbs. 

Nominal Braking Power 

70% on 50 lbs. 

58.5% on 50 lbs. This is equivalent to 

85% on 60 lbs. 

40,000 lbs. 

Car—Light Weight 

40,000 lbs. 

140,000 lbs. 

Car—Loaded Weight 

FOR FULL SERVICE APPLICATION. 

(50 lbs. Cylinder Pressure Obtained.) 

140,000 lbs. 

58.5% 

Braking Power—Light Car 

70% 

16.7% 

Braking Power—Loaded Car. 

20% 

41.8% 

Difference between braking power 



on loads and empties 

FOR 10-POUND REDUCTION. 

50% 


(20 lbs. Cylinder Pressure Obtained.) 

23.5% 

Braking Power—Light Car 

28% 

6.7% 

Braking Power—Loaded Car 

8% 

16.8% 

Difference between braking 



Power on loads and Empties. 

20% 


By raising brake pipe pressure to 90 lbs. instead of increasing 
nominal braking power to 70% on 50 lbs., as proposed, the service 
operation is not affected. That is, for reductions up to that which 
will produce a brake cylinder pressure of 50 lbs., the braking power 
is the same as at present. The obtainable or reserve power of the 
brake is considerably increased, however, since the service equali¬ 
zation pressure is increased from 50 lbs. to 65 lbs. which would give 

76% Braking Power—Light Car. 

21.7% Braking Power—Loaded Car. 

54.3% Difference between Braking Power 
on Loads and Empties. 


Brakes in Freight Service 


19 


From the above it is seen that if we increase the braking power 
from 70% on 60 lbs. to 70% on 50 lbs. (85% on 60 lbs. cylinder 
pressure), it will result in a net gain of 11.5% braking power on the 
light car and 3.3% on the loaded car for a full service application— 
the difference between the braking power on loads and empties 
being increased from 41.8% to 50%. If the desired increase is 
obtained by leaving the nominal braking power the same as at 
present standard (70% on 60 lbs.) and increasing the brake pipe 
pressure carried from 70 lbs. to 90 lbs., for a full service applica¬ 
tion, the gain on the light car is 17.5% and on the loaded car 5%. 
It should further be noted that up to 50% (the service equalization 
pressure when 70 lbs. brake pipe pressure is carried), there is no 
difference in the braking power obtained for a given cylinder pres¬ 
sure. That is, by raising the brake pipe pressure to 90 lbs. the brake 
remains the same for ordinary service reductions, but the ultimate 
braking effort is advanced by 17.5% on the light car and 5% on 
the loaded car. While this, of course, results in a wider differ¬ 
ence, (54.3%) between the braking power on the.loads and empties, 
it should be remembered that this is for 15 lbs. higher brake cylin¬ 
der pressure than that for which this difference under the proposed 
standard is only 4.3% lower. Furthermore, this difference can 
only be attained by a full service reduction, during the progress 
of which the slack has an opportunity to adjust itself harmlessly, 
and while by increasing the leverage, the difference, as pointed out 
above, obtains on all partial as well as full service reductions. Again 
by increasing the brake pipe pressure, the gain is available on all 
cars alike, gives a large reserve power, during ordinary service appli¬ 
cations of the brake and requires only an adjustment of the feed 
valve to accomplish the same, while the benefits of an increased 
nominal percentage of braking power are obtained only on those 
cars whose levers have been changed accordingly. 

Slide 774 (see appendix) illustrates graphically the difference 
in braking power on loaded and empty cars. Taking for example 
a 10-pound reduction with 8-inch piston travel and 70% braking 
power, you will note that while the braking power on the loaded 
car is less than 10%, it is more than 30% on the empty car, or, 
in other words, over three times as great. If, however, we assume 
a condition which frequently occurs in actual service; that is long 
(or relatively long) piston travel on the loaded cars ahead, and 
short (or relatively short) piston travel on the' empty cars behind, 


20 


Brakes in Freight Service 


etc., it will be seen at once by the chart that the variation in brak¬ 
ing power between the loaded and empty portions of the train is 
very much emphasized. For instance, with the 10-pound reduc¬ 
tion as mentioned, we have a braking power on the loaded portion 
of about 8%, while assuming for the sake of illustration of a piston 
travel, of 6 inches on the empty cars, we have a braking power of 
about 47% or almost six times as great. If, on the other hand, 
the higher braking power of 85% is employed, and a 10-pound re¬ 
duction is made with normal piston travel, the braking power on 
the loaded car is but a trifle over 10%, whereas that on the empty 
car has been raised to 37J%. From this it will be seen that the in¬ 
crease in percentage on the empty car is far greater than that on 
the loaded car, which latter in fact is but trifling. Consequently, 
the difference between the two is greatly exaggerated. 

In the case of unequal piston travel cited above, if the braking 
power were raised to 85%, that of the loaded car when a 10-pound 
reduction is made would be increased only from 8% to 9%, where¬ 
as that of the empty car would be increased only from 47% to 
56%, the undesired difference in braking power being thereby 
greatly aggravated. 

USE OF RELEASE AND RUNNING POSITIONS. 

I feel a few words should also be said regarding the' use of re¬ 
lease and running positions on the brake valves, for it is here that 
the engineer may start trouble, for with the high pressures and 
large main reservoirs and the long trains of today, it is very easy 
to overcharge the head end of the train as compared with the 
rear and with a short train to overcharge it throughout as com¬ 
pared with the adjustment of the feed valve. Many detrimental 
effects result from this, such as stuck brakes, flat wheels, cracked 
wheels, undesired quick action and where successive applications 
are made, as in grade work, in the brakes on the head cars doing 
practically all the work. 

Another result which I would like to impress upon all is that a 
great many engineers think that because the gauge shows that the 
pressure has risen very rapidly, and higher than the auxiliary 
reservoir pressure is intended to be, that the brakes are released 
and consequently open the throttle, while, as a matter of fact. 


Brakes in Freight Service 


21 


this is a condition that exists only on the first few cars of the train, 
the pressure of the rear not having yet increased sufficiently to 
force the triple piston to release position. In fact, twenty-five 
cars back from the engine, it cannot be told from a gauge whether 
the handle is in release or running position. With modern engine 
equipment, the brake valve should not be held in release position 
more than 15 seconds when releasing brakes is the object. The 
exceptions to this rule are when charging up a train, or under 
some conditions of grade work. 

An inspection of Slides 855, 856, 857, 858, 859, 860 and 861 of the 
Appendix, accompanied by a perusal of the explanation will demon¬ 
strate the importance of this phase of the subject. 

It will be seen from what I have said that brake manipulation 
and operation in freight service involves more than the judgment 
of the engineer in moving the brake valve handle back and forth. 
In fact, much more is dependent upon the condition of the train 
and the brakes than upon the manipulation by the engineer. Nay, 
more, it will be seen that conditions may often make judgment 
impossible and insure shocks and break-in-twos in spite of it. Com¬ 
prehension and application should come down from the officials 
to the engineer and instruction and discipline up to the engineer 
through the car men arid trainmen. Until this is done, we are try¬ 
ing to cure our troubles by pecking away at the effect instead of 
what is more logical and reasonable, namely, dealing with the 
cause. 

In concluding this subject, I desire to mention some of the 
changed operating conditions which have made much more diffi¬ 
cult the control of freight trains, then analyze a proposed change 
or two expected to improve conditions, after which offer a few 
suggestions, the adoption of which will greatly reduce shocks and 
break-in-twos. 

First: Heavy and more powerful locomotives (often two of 
these used to a train)—increasing the difficulty of starting trains 
without shock—making long and heavy trains possible, this, self- 
evidently, making the control more difficult—also severe strains, 
are set up when the brakes are released on these heavy weights 
before it is possible to obtain the release of the brakes on the rear: 
also with freight trains bunching the slack (because the brakes 
on the engine, if in good order, will produce more retardation than 


22 


Brakes in Freight Service 


those of the cars), then when the brakes take hold on the cars 
at the rear (generally empties), or, if for any other reason- the 
slack runs out, shocks are likely to result. With passenger trains, 
the reverse is true, as the cars are always being retarded more than 
the engine, and therefore the train is stretched. 

Second: Cars of greater capacity, therefore, greater weight, 
and this without corresponding increase of the light weight, thus 
reducing the braking power when loaded to a greater extent than 
with the older cars. This condition creates a greater difference 
in braking power between the forward and rear end of the train 
when we have loads ahead and empties behind. 

Third: Different percentages of braking power, some roads 
using 70 per cent, and others as high as 90 per cent, of the light 
weight; others, again, intermediate percentages. These things all 
tend to make the braking power unequal (and, of course, the longer 
the train, the worse it will be, because the time element “cuts quite 
a figure”); so much so, that if we got together a combination of 
long trains—-loads ahead—empties behind—(and if these empties 
have short piston travel, the situation is aggravated to a remark¬ 
able degree), high percentage of braking power—slow speed and 
brake application (particularly if made by an engineer who does 
not or has not taken these things into consideration),—a break- 
in-two is to be expected. 

Fourth:. Different sizes of brake cylinders. And this has more 
effect than most people think. For one reason, because the total 
leverage will be varied by the weight of the car and size of cylin¬ 
der, thus the piston travel, so important a factor with light or 
medium brake pipe reductions, will vary greatly for the same 
shoe wear—this is self-evident with cars under-cylindered or when 
equipped with brakes with which the service and emergency cylin¬ 
der pressures are the same. 

Fifth: Varying brake pipe pressure: This changes the time 
element, often resulting in a heavier or a lighter application than 
was intended. 

Sixth: Varying brake pipe volume: Thus modifying the time 
of application and release; and this far beyond direct proportion. 
The effect of this will be seen when it is borne in mind that men 
who have been coupling up and handling a fixed and limited num¬ 
ber of cars—therefore, an approximately constant volume-^often 


Brakes in Freight Service 


23 


fail to release the rear brakes of a long train before opening the 
throttle, or take into consideration the length of time it takes to 
get the air out or back into the brake system of long trains. 

Seventh: “All air trains,” and from a train handling stand¬ 
point this is one of the most important factors, as no matter what 
the make-up of the train, the brakes must be cut in within certain 
limits, therefore, if the train is so made up that excessive - and 
damaging retardation takes place at the rear, the scheme of cut¬ 
ting out every other brake cannot be resorted to, as was done on 
some roads until recently, where “all air trains” were being handled. 
(By “all air trains” is meant that the brake pipe is charged with 
air from the engine to the rear of caboose). Not only this, but it 
is plain that more knowledge, greater skill and constant thought 
is required on the part of all concerned to deal with conditions 
so variable as those involved in the make-up and the means of 
controlling the trains to today. In other words, the human equa T 
tion is more of a factor than ever before. This, I am happy to say, 
is beginning to be realized, and soon, I hope, many will be con¬ 
vinced that more consideration must be given to the condition 
under which the brake operates, if the results due to lack of con¬ 
sideration are to be avoided, for it is a fact that there are proper 
and improper conditions for the brake as for other mechanical 
devices, and there is more to it than simply attaching it to a car. 

Eighth: In this connection, it may be well to mention that the 
many different styles of draft rigging have quite a bearing on the 
matter of shocks in trains; those possessing the greatest dissipat¬ 
ing power with no recoil being, in my opinion, very necessary to 
meet the conditions of today, as the brakes and engineers can hardly 
be expected to compensate for all the changes that have taken 
place. 

Ninth: Other things might be mentioned and elaborated upon 
—such as a greater number of parallel tracks, more yards and the 
frequency of trains, but I think the foregoing will help keep in mind 
the complexity of the problem when what follows is being con¬ 
sidered. 

Many schemes are proposed to alleviate these troubles; good, bad 
and indifferent, most of them bad because they do not touch the root 
of the matter. In one detail they are nearly all alike, viz., in be¬ 
ginning with the engineer, while here is where they should end. 


24 


Brakes in Freight Service 


The brake is a good servant, but a bad master, and it becomes re¬ 
bellious when contending with impossible conditions and is some¬ 
what sensitive to neglect. 

A quasi-plausible scheme actually put in effect on a great rail¬ 
road for a time (a short time only' for the remedy was worse than 
the disease) and recently considered by another, was to reduce 
the pressure carried in the brake system to 50 or 55 pounds. There 
were three advantages to be gained by this, so it was said: 

(1) That the braking power would not be so great for a service 
reduction and, therefore, that the severity of the shocks and break- 
in-twos would be reduced. This, however, would only hold true 
for heavy reductions, as, for instance, a 10-pound reduction would 
give the same cylinder pressure whether the brake pipe pressure 
be 70 lbs. or 55 lbs., other things being equal. And, as the shocks 
and break-in-twos will usually occur, if at all, by the time a 10- 
pound reduction has been made, it is plain that reducing the pres¬ 
sure would be of no help in this case; this, of course, applies to 
service applications. 

(2) That undesired quick-action will occur less frequently. 
This, however, will not necessarily follow, as, while undesired quick- 
action due to friction caused by pressure on the slide valve may 
be reduced, yet undesired quick-action due to slowness of reduction 
will be increased. Therefore, the gain in one direction is off¬ 
set by the loss in the other, and I believe more than offset. More¬ 
over, there should be no undesired quick-action with 70 lbs. brake 
pipe pressure carried, and if there is, it can be corrected much 
more effectively by keeping the apparatus in a workable condition 
than by reducing the efficiency of the brake; which means in the 
last analysis its abandonment. 

(3) That in the event of undesired quick action the maximum 
braking power possible to obtain with the lower pressure will be 
less than with the higher; and here we have the only reason that 
is even plausible. But even this can only be granted when it is 
assumed that we are compelled to choose between two evils, viz., 
(1) air brakes improperly maintained and operated and, (2) a 
lower efficiency of the brake both in service and emergency appli¬ 
cations. It is self-evident that the brake will be less efficient with 
an emergency application, but it may be necessary to point out 
that for service applications not only would the braking power 


Brakes in Freight Service 


25 


of an equalized application be less, but the reserve for partial ap¬ 
plications would be much less in one case than in the other. In 
other words, where with 55 lbs. brake pipe pressure the operator 
would have to use a reduction that would produce equalization to 
control his train and therefore eliminate any reserve and make a 
stop impossible; on the other hand, with the higher pressure the 
same reduction would give him the same train control and leave 
a reserve braking power equal to that already obtained, thereby 
making a stop possible if called for. 

The above, I believe, covers all the arguments that can be ad¬ 
vanced in favor of the lower pressure, and the analysis shows that 
they are by no means sound and certainly not sufficiently decisive 
to warrant the change. It may be said (but certainly not ad¬ 
vanced as a reason) that 55 lbs. will control an empty train more 
effectively than 70 lbs. will a loaded train, and this may be granted, 
but it does not follow from this that the empty train with 70 lbs. 
has any surplus of control, and until this is proven, it would not 
appear wise to lower the braking power of the empty train simply 
because the loaded train is under-braked. 

Moreover, these other things should be considered; that it will 
be difficult to secure the change of pressure when changing an en¬ 
gine from an empty train to a loaded train, and vica versa, and 
no doubt you would often find the loaded train carrying 55 lbs. 
and the empty train 70 lbs. of brake pipe pressure, and partic¬ 
ularly I believe you would find that once the engineers were led 
to believe that 55 lbs. was a panacea for their troubles, it would 
be difficult to prevent their carrying the lower pressure when they 
should carry the higher—especially where the train is made up 
of loads and empties; also it should be considered whether it is 
trains composed of all empties that are breaking in two in the 
great majority of cases. I am of the opinion that you would find 
that it is where a long string of empties are behind loads that this 
occurs; if this is so, even a consideration of 55 lbs. cannot be per¬ 
mitted. 

Another scheme actually put in practice by some roads is to put 
up the percentage of braking power on empty cars. This is done 
ostensibly to increase the braking power for the cars when loaded. 
There may be some excuse for roads doing this who have heavy 
grades to negotiate, for perhaps they consider it a choice between 


26 


Brakes in Freight Service 


putting up with break-in-twos or risking run-aways on the grades, 
or perhaps they have empties one way and loads the other, as for 
example the D. I. & R. 125 per cent., or perhaps again they are 
wise and do not haul empties and loads in the same train, knowing 
that by increasing the braking power on the empties they have 
made this more risky and impracticable than ever before. How¬ 
ever, the other roads have to handle the cars, so somebody gets the 
effect. 

As it is unequal braking power that is responsible for shocks, 
anything that tends to this is pertinent to the question of train 
control. Therefore, the analysis of this practice, on pages 15 to 
21, is in order. It must be understood that as some look at it, 
it is a choice of two evils—braking power too low for grades, or too 
high for empties behind loads—but if they increase the braking 
power some one is going to have greater difficulty in smoothly 
controlling some classes of trains. 

In this connection I may also point out that general recom¬ 
mendations and instructions apply to general conditions; particu¬ 
lar and specific conditions requiring and permitting considerable 
modification of such general recommendations to suit the case, 
and it is only with an intimate knowledge of and with particular 
reference to such cases that one can be specific. 

There are other schemes no more effective or practical than this, 
their chief virtue being a desire to find some way to reduce shocks 
and break-in-twos. As these undoubtedly arise from unequal 
braking power in different parts of the train, which may be tem¬ 
porary, as, for instance, the brakes applying more quickly or with 
higher cylinder pressure at the head end of the train than at the 
rear; or permanently, as, for instance, when there are loads ahead 
and empties with short piston travel at the rear, I will point out 
that shocks or break-in-twos may be greatly reduced by: 

(1) Forbidding the use of the straight air brake of the engine 
to bunch the slack of the train before applying the automatic 
brake. I am aware that you will quote Westinghouse Instruction 
Books against this rule, but these instructions, as well as many 
others, were given to suit conditions very different from those of 
today. It is- a self-evident fact that when conditions change, old 
rules and instructions become obsolete, or must be changed to suit 
the new conditions. A slight review of the instruction regarding the 


Brakes in Freight Service 


27 


use of straight air to bunch the slack gently, may be sufficient to 
demonstrate this. This instruction given when only part “air 
trains” were the rule, was necessary, as if the brakes were applied 
on the braked cars before the slack was in from the unbraked cars 
behind the shock was sometimes equal to a collision. Now, if the 
slack is bunched with an “all air train,” particularly with empties 
at the rear, the running out of the slack, as the brakes take hold 
at the rear, often results in a break-in-two and certainly in a shock 
which is damaging to both equipment and lading. 

Personally, I doubt the advisability of using straight air at all 
for train control, as so much judgment and care is required to 
use it when and where it will do good and not harm. I mean now 
for making stops or slow-downs—for if it is applied heavily, a colli¬ 
sion is often the result—if applied and released and the throttle 
opened, while the cars are bunching or still bunched at the rear, 
a break-in-two is in order. Of course, there are critical speeds and 
conditions when damage is more likely than at other times. Straight 
air on the engine is of great value when used at the proper time and 
place, but it was not intended to take the place of the automatic 
brake in controlling trains, nor to be used because unfair conditions 
impair the efficiency of the automatic brake. 

(2) By placing loads at the head end of the train and shortening 
the piston travel, and the empties behind and lengthening the 
piston travel,—bringing about a greater difference in cylinder 
pressure for graduating applications and thereby securing greater 
equality of braking power between loads and empties; at the same 
time the emergency pressure will be only slightly reduced. 

(3) Alternating loads and empties. 

(4) Applying the brakes before the slack is bunched as, for in¬ 
stance, before the steam is shut off. 

(5) Instructing engineers not to use emergency applications 
unless actual emergency exists; not, for instance, to consider every 
switch, water-tank, or coal shute as an emergency zone and apply 
the brakes accordingly. 

(6) Not to use heavy initial service reductions, unless speed is 
low and stop intended. 

(7) Do whatever is necessary and possible to secure uniform ap¬ 
plication of brakes. 


28 


Brakes in Freight Service 


(8) Do all possible to insure that it is the engineer that is con¬ 
trolling the application of the brakes and not the brake pipe leak¬ 
age, and in general that the brakes are maintained in such condi¬ 
tion that the anticipated operation is possible and obtained. Give 
the engineer a chance. 

(9) Avoid, if possible, applying or releasing brakes when pas- 
ing over “Hog-backs” or round curves. 

(10) Avoid' releasing the brakes before the brakes have ceased 
to apply during a reduction. 

(11) Avoid, whenever possible, applying the brakes again after 
a release, while the brake pipe pressure is higher at the head end 
than at the rear, in other words, equilibrium of pressures should 
be established throughout the train, as otherwise the head brakes 
will apply and those at the rear will not—therefore, the cars may 
be bunched and if the brakes at the next reduction take hold, this 
in conjunction with the recoil of springs will produce severe shocks. 

(12) Avoid releasing brakes at speeds below ten miles per hour 
unless the locomotive is equipped with “ET” or the forward cars 
with “K” triple valves, as otherwise brakes releasing at the head' 
end permit the retardation still existing at the rear to stretch the 
train—sometimes beyond the strength of the car connections. 

(13) Avoid, whenever possible, having too many cars'at the rear 
which are levered for a high braking power, as for instance, cars 
(of which there are many in service) upon which the braking 
power is calculated *at 90 % on 60 lbs. cylinder pressure—it is' 
obvious that this aggravates the already existing inequality of 
braking power between loads and empties and is in effect the same 
as attaching so many passenger cars to the rear end of a freight 
train, which no one who expected smooth operation would do, un¬ 
less the brakes on these rear cars were alternately cut out. 

(14) Locate the places where accidents of the kind under con¬ 
sideration most often occur and advise extra precautions, for, un¬ 
doubtedly, you will find that there are certain track or signal con¬ 
ditions, which, in conjunction with an application or release of the 
brakes (to say nothing of the starting of trains), tend to produce 
shocks, and this, added to the already numerous factors tending in 
the same direction, often result in a “break-in-two.” I think you 
will find that a number of your men are cognizant of this fact and 
have these places pretty well “spotted” and are governed accord- 


Brakes in Freight Service 


29 


.ingly and, therefore, do not have near the trouble that some others 
do who either cannot reason back from effect to cause or are care¬ 
less. To these latter a little information and advice may mean a 
close approach to the results obtained by others who learn by ex¬ 
perience. I think I can illustrate what I mean by this paragraph 
by calling to your mind how necessary it is that an engineer, new 
to a division, become acquainted with the track, etc., before the best 
results can be expected. In other words, other things being equal, 
his proficiency depends largely upon his knowing the condition 
under which he operates. 

(15) At speeds of over 20 miles per hour make a light prelim¬ 
inary reduction, followed by continuous heavy reductions when 
speed is reduced to, say, 8 miles per hour and stop intended. At 
low speeds, when stop is intended, make a continuous full reduc¬ 
tion. The reason for this is to keep the slack bunched as the brake 
will naturally be applying with greater power on the head end than 
at the rear, therefore tending to keep a steady push toward the 
engine. 

(16) If slow-down only is desired, it is better to make a light 
reduction, far enough back, than a heavy one to accomplish the 
same result in less distance; in the former case, when the release 
is made (even if at slow speed) there should not be braking power 
enough to cause shock, while in the latter case the reverse is true. 

(17) Enforce the rule that with long trains the engine must be 
cut off from the train whenever an accurate stop is imperative, as 
for coal and water, and insist that, after again coupling to the train 
that sufficient time be allowed for the brakes to release before trying 
to start the train. 

(18) A terminal inspection that will discover and send to the 
repair track all cars, particularly draft gear, that are likely to cause 
trouble on the road. There is no doubt that a great number of 
break-in-twos are due to defective brakes and draft gear being 
allowed to leave terminals, and it is hardly a question whether it 
is wiser to take chances than to adopt a safer method. Of course, 
it is cnly a matter of time before the inevitable happens, but each 
thinks it possible that the car will reach the next terminal. Plainly, 
as long as chances are taken in these matters, even the best of care 
on the part of those operating the train on the road, cannot pre¬ 
vent a great many break-in-twos. 


30 


Brakes in Freight Service 


As stated, the difference in braking power is held to be the cause 
of shocks, etc., and the foregoing include at once the reason why 
and how it can, in a large measure, be overcome and uniformity 
more closely approached. It is plain that to do this involves both 
effort, expense and inconvenience, but my railroad experience 
taught me this was unavoidable and to be expected in railroad opera¬ 
tion, and I may say that in the matter under consideration, what 
has been outlined permits of a choice between what exists and what 
we desire , to determine which the benefits versus the cost will be the 
governing consideration. 

In conclusion, it may be well to state that the cause of break-in- 
twos may be traced to the method of handling the brakes—to the 
condition and class of draft gear and brake equipment—to the 
make-up of the train and the kind of train service—it being un¬ 
derstood that the human equation is a qualifying factor at all 
times. All these causes taken singly or collectively are such at 
times as to make a break-in-two difficult if not impossible to avoid. 

“Break-in-twos” are caused by greater braking power at the 
rear than at the forward part of the train. This class of break-in- 
two often causes much inconvenience and some loss, but as it is a 
separation and not a collision the danger of serious accident is not 
great, unless following trains are too close. 

“Buckling” is caused by greater braking power at the forward 
end of the train than at the rear. This occurrence not only means 
inconvenience and loss but that the danger of serious accident to 
both the train to which it occurs and to others of either direction is 
very great, as the cars may be scattered over the different tracks. 

I have gone into this part of the subject somewhat fully, if not 
completely, because I should at least do so sufficiently, to permit of 
your weighing both sides of the question. 

The number of things mentioned show the complexity of the 
problem and many may say that no one can take all these things 
into consideration. This may be so, but they exist and must be 
dealt with as a condition and not a theory, and in proportion as 
they are taken into consideration will improvement be made, 
and, what is also important, the responsibility will be placed where 
it belongs, which is the first step toward desired results. 

It will be seen that there are four elements involved in every 
brake operation, namely: 1st, time: 2nd, amount of reduction or 


Brakes in Freight Service 


31 


change of pressure in the brake pipe; 3rd, amount of cylinder pres¬ 
sure obtained, and, 4th, percentage of braking power. Only one of 
these is fixed, viz.—the percentage of braking power. That is, a 
given pressure in the cylinder gives a certain braking power; all 
the rest are variable. For instance, the time required to reduce the 
brake pipe pressure a certain amount is varied by increasing or de¬ 
creasing the length of the train because this changes the volume of 
air in the brake pipe. The amount of reduction required to obtain 
a given cylinder pressure is varied by the ratio of the reservoir to 
the brake cylinder and the cylinder pressure obtained from a given 
decrease in reservoir pressure is varied by the ratio of the brake 
cylinder to the reservoir, which ratio is varied by an increase or 
decrease of piston travel, as this in effect increases or decreases the 
size of the brake cylinder. Plainly, then, all these elements must be 
kept in mind when considering any problem involving train control 
and it is only by knowing the relationship existing between the dif¬ 
ferent elements that the cause of the results obtained can be deduced. 

The control of trains has become a. much more complicated prob¬ 
lem than heretofore, much knowledge of all the conditions in¬ 
volved is necessary, and the best talent available will be taxed to 
the limit to get the most economical efficiency, and yet strange as 
it may seem, these things are realized only by the few. 

The air brake has advanced in the past year or two from being 
considered chiefly a safety appliance that was required by law to be 
applied, to an absolute necessity in the handling of freight and pas¬ 
senger trains, and its operation must be properly understood to make 
it a dividend earning asset. 

The President : The speaker wishes to know if you prefer to ask 
questions now, or if you want to ask the questions as he throws the 
slides upon the screen ? 

A. J. Cota (C. B. & Q.): I believe it would be the best plan to 
have him put on the slides first. 

Mr. Turner : In the paper read it was pointed out, among other 
things, that the percentage of braking power, the cylinder pressures 
obtained, the effect of varying piston travel, and the time element 
were very important factors and modify both the operation and 
the manipulation of the brake. These elements and their effects 
can be shown by curves and charts even better than in actual opera¬ 
tion and a number of these are referred to in the text. 


32 


Brakes in Freight Service 


The majority of these curves and charts are traced from indicator 
cards. The indicators used are essentially similar to steam cylinder 
indicators, but in addition have an electrical attachment connected 
to a clock which registers the time—the time of the commence¬ 
ment of the experiment and its duration being registered simultan¬ 
eously throughout the whole train, consequently, we not only have 
the time for the whole experiment, but also the differences in time 
between any similar operation throughout the train. In other 
words, we know the time of any given operation at any part of the 
train. Other of these curves are plotted from calculations, as they 
are simply questions of proportion, and one'of their values is that 
they serve to show how important is the maintaining of the proper 
proportions and that in so far as they fail from what is proper 
the operation is adversely affected. 

The President: We would be glad to have you ask such ques¬ 
tions as you may have in mind and we will give Mr. Turner an op¬ 
portunity to reply to them before the minutes are published. 

i Mr. W. E. Symons (C. G. W. Ry.): Owing to the lateness of the 
hour, and the fact that Mr. Turner has talked for a couple of hours, 
giving us a very interesting paper, and I might say, a highly scien¬ 
tific lecture, I think it would be an imposition to ask any questions 
here tonight that would involve further discussion. There are one 
or two points which occurred to me that I would like to mention, 
with the suggestion that Mr. Turner be furnished a copy of the 
questions asked (and on which I would like permission to amplify), 
so that he can reply by letter in his closure. 

Question 1. In the earlier part of Mr. Turner’s paper he men¬ 
tioned the fact that the braking efficiency of cars varied from 100 
per cent to as low as 44 per cent, or, we might say. a range of differ¬ 
ence in efficiency of 56 per cent, and while the details were not 
given as to just all of the causes that might contribute to this, yet 
it might occur to some that the different makes of brakes and dif¬ 
ferent types of the same make, might have a little something to do 
with this condition. 

It was also suggested by the author, that the switching of cars to 
certain parts of the train would minimize this trouble to a great ex¬ 
tent, and while this is true, yet under present operating conditions, 
this plan may be considered impossible, and of course it is necessarily 
incumbent upon the motive power officers to take care of the brake 


Brakes in Freight Service 


33 


equipment in such a manner, that no matter what distribution is 
made of this diversity of types and conditions we should get prac¬ 
tically what might be called average results, and if there is anything 
that Mr. Turner can tell us in his closure that would throw addi¬ 
tional light on the best thing to do to the brakes now on our cars 
(aside from suggesting the switching of the cars around), that would 
be a very good thing for the motive power department and mechan¬ 
ical officers to have to work upon. 

Question 2. Another point in connection with that same question 
was, where the piston travel varied, causing a wide range of differ¬ 
ence in cylinder pressure. My recollection is the author said that 
a great deal of trouble resulted from this inequality of piston travel, 
and the consequent difference in pressure of the brake cylinder was 
largely due to the faulty location or arrangement of the foundation 
of the brakes. Now, if I am right in that, I want to ask the author 
if he would kindly explain, if that was the fault of the railway com¬ 
panies in applying brakes to cars that they build, or in making re¬ 
pairs, or is it a fault in the designs furnished by the air brake build¬ 
ers? I am assuming that all brakes are applied according to prints 
furnished by the Air Brake people, therefore, if the foundation of the 
brake is faulty, or in any manner affects their operation or the 
proper equalization of pressure, then the fault may be due to the 
design, and not chargeable to the Railroad Companies. 

Question 3. Another question has occurred to me in connection 
with this matter that I do not think the author mentioned. With 
some systems of levers, or brake arrangements, the brake rod lies 
pretty well out to the side of the car, in fact, on some trucks with 
side bearings spaced 60" radius, the brake rod lies next to the side 
bearings, and sometimes on the outside, with the upper end of the 
brake lever almost in line with the side bearings, and in rounding 
curve, with this brake rod on outside of the curve, I would like to 
ask if this will have the effect of shortening the rod, -particularly 
on rounding a very sharp curve? If that is true, is it then not a 
fact that this might exert some influence on the derailment of a 
car. Assuming that curve elevation was arranged for a high rate 
of speed, in which case the centrifugal force would result in the 
equilibrium of the car body, but the train moved at a slow rate of 
speed around the curve, allowing the cars to lean heavy on the 
inside of the curve, and bearing hard on the inside side bearing, if 


34 


Brakes in Freight Service 


that was the case, and the brake rod was on the outside, and this 
condition resulted in shortening the rod thus placing more strain 
on it than when the car was on the straight track, would it not have 
the effect of assisting the leading outside flange of the truck wheel 
in climbing the rail. Would not this combination assist somewhat 
in a derailment which otherwise might not occur if the train was 
going at a higher rate of speed, or was on a straight track? 

Question 4. Another point in connection with friction draft gears, 
which possess, as we all admit, many good points, but just what 
effect they would have, or what percentage of effect in the elimina¬ 
tion of damage to cars or contents, the author did not state, and I 
would be glad if he would elaborate a little on that, if he so disposed, 
particularly on the type of draft gear, spring or friction that is con¬ 
sidered most efficient in service and economical in repairs. 

In the matter of sending cars to the rip track when they need re- 
pairs, that point is a very good one, and while of course it would 
result in a highly improved condition of the brakes, I rather suspect 
if that were followed out strictly, we would have to stop a great 
many important trains with high grade freight when they really 
could go forward, and while I think the instruction or advice given 
to railways is very good, yet I am inclined to think the railroads 
would hardly be able to carry this out, so long as the present method 
of handling cars is in vogue that we now tolerate in switching yards, 
which results in much damage to draft gear in general. Still, if 
the author feels that recommendation can be carried out, I would 
be very glad if he would elaborate on that point. 

There are a number of other points that are quite important, 
but I feel, owing to the lateness of the hour I have mentioned all I 
should, and in justice to the author, I would not ask him to reply 
to them this evening. 

Prof. L. E. Endsley (Purdue University): I appreciate the 
difficulty experienced by the author in preparing a paper like this 
in so short a time, and I move you, Mr. President, that the Club 
extend a vote of thanks to Mr. Turner for this very excellent paper. 

Mr. Turner : I should like to say one word relative to this even¬ 
ing, and that is, that I thank those who have listened to the paper, 
which was rather technical in places. There were a great many 
points brought up in connection with the work required to make 
it clear, for an evening like this, a great deal of elaboration, there- 


Brakes in Freight Service 


35 


fore I feel that the paper will be much more beneficial when printed 
than it has been tonight. I know when I was studying those points 
over from the practical point of view that it took me more time to 
figure out all there was in it; it did not take very much time to 
put it on paper, but it takes a lot of time to figure out all that is 
involved in it, and therefore the effort was not so much to write 
a paper that would be satisfactory or create an impression this 
evening, but something that would bear looking into. The fact is, 
gentlemen, the conditions enumerated in that paper lie before us 
and they must be dealt with, and if any of you feel like backing up 
the engineer or-the conditions that exist, the best thing to do is to 
take that paper and see whether you can remedy it, or whether you 
will put up with the trouble cheerfully. 

The President: I think it is entirely unnecessary that the au¬ 
thor of the paper should offer any apology. Personally I feel, and 
I am sure the rest of the members feel that it is a paper we shall feel 
proud of having presented to us. 

It has been regularly moved and seconded that a vote of thanks 
be extended to the author of this very excellent paper. All in favor 
signify by saying “Aye.” Contrary “No.” It is unanimous. 

Adjourned. 


36 


Brakes in Freight Service 


appendix 

After the paper was read these curves and charts, by means of a 
stereopticon, were thrown upon a screen and their characteristics 
explained and the effects of these in train control amplified. Obvi¬ 
ously, such explanation, even though taken by a stenographer, 
would be unintelligible in print, as a pointer was employed to desig¬ 
nate this or that line or figure, and which cannot be reproduced in 
print. Therefore, it has been thought best to give a brief explana¬ 
tion of the charts instead of trying to reproduce the stereopticon 
lecture, cross references being given in the text of the paper to this 
explanation and from this back to the subject matter these are in¬ 
tended to supplement and emphasize. 

Until very recently air brake questions have been settled strictly 
according to individual opinion—there being no standard of refer¬ 
ence except the individual who was supposed to be an authority in 
air brake matters. Now these questions are settled by a reference 
to a standard written by the apparatus itself; consequently, we have 
but one answer and that the correct one. To a question involving 
like conditions, it is no uncommon thing to get several different 
answers from the different authorities; any one of them may be 
right and all of them may be wrong, for each authority is probably 
assuming different conditions, as but few questions are asked which 
are complete, or if the question is complete, it is so general in char¬ 
acter that a large volume would be required to completely answer it. 
For instance, What will cause a slid flat wheel? 

Slide 642 illustrates graphically, when compared with Figures 824 
and 825, how length of train affects the application of the brake both 
as regards pressure and time. It will be seen that with the old type 
of triple valve very little cylinder pressure was obtained on any of 
the cars and that there was an interval of 45 seconds between the 
application of the first and last brakes in the train. The curves for 
the “K” valve show that not only can the difference in time of appli¬ 
cation be overcome in a large degree, as here the interval between 
the first and last brakes was but 10 seconds, but also that a more 
effective cylinder pressure was obtained. 


Brakes in Freight Service 


37 



H-Trip/e Va/ye- 

30 Sra/res app//ed 

60 3rare p/s to ns moved $ to 6 

/O £5 ra/res faded /o /Trove . 

/06 Car fra/r? — 70 /ds t /brarrep'pe pressure 
S/d. Srarce p/pe rec/ueP/on 


SLIDE 642 . 




















38 


Brakes in Freight Service 


Slide 643 differs from the preceding in that a 10-lb. reduction in¬ 
stead of a 5-lb. was made, and a comparison between the two sets of 




1 

<0 

! S 

^ •§> 




<u 

I 

je; 

r 


cylinder cards shows how much more effective and uniform in opera¬ 
tion the brake is when the time element in the application is reduced 
to a minimum. 


























Brakes in Freight Service 


39 



Slide 644 differs from the preceding in that the reduction was 15 
pounds instead of 10 pounds. 


















_ /st Car 
2.5 th - 


Slide 645 differs from the preceding in that the reduction was 20 
pounds by a full service application instead of 15 pounds. A glance 
at this set of charts will show that they are self-explanatory. As to 


0 * ' • > 



appreciated by those who have had experience in brake matters, or 
who are willing to be governed by those who have. 















Slide 824. The cylinder cards of this figure, when compared with 
Figures 642 to 645 inclusive, illustrate what a great difference in 
time and pressure exists between a long and short train, as here the 
interval of time between the application of the first and last brakes 



\0 LB. REDUCTION 



6o 




was but 6 seconds as compared with 45 seconds with a 100-car train 
and same type of triple valve; while with a 20-pound reduction 
maximum cylinder pressure was obtained in about 35 seconds in¬ 
stead of 105 seconds with a 100-car train. 

























42 


Brakes in Freight Service 


3/^57:^ u>*.* 

<x5 2 ^ 


!2 


■i-u. 


5LB. B.P REDUCTION. 


n— T —r 

4-0 50 


"i 1 r 


10 


2.0 


30 




































Brakes tn Freight Service 


48 


START. 



FULL LINES K*- 

DOTTED * H*- 


SLIDE 707 . 



















































44 


Brakes in Freight Service 


note: : 

SCALE indicates time: I IN seCOMD-S. 





DOTTED 


SLIDE 709 





















































Brakes in Freight Service 


45 


note : 


START 


LE. I fsj O I 


TIME IN SECONDS. 



rULL. LINES - 

DOTTED •• H*- 


SLIDE 711 





























































46 


Brakes in Freight Service 


time in seconos. 



DOTTED- H*- SLIDE 713 . 






























































I st Car 


Brakes in Freight Service 


47 







<*c 

}• 

$ 

V 

0 

\» 

§ 

cc 

* 




(0 

•o 

1 

I 

8 


I 


t 

8 .5 

o 

$ 


cf .* 

I 


¥ 

5 

QQ 


S 

* 

$ 


>2 

1 

$ 


(0 

■8 


\) 

00 

G5 

LO 

0 

Vj 

Cv 


W 

Q 

L 


*> 

0) 

rf* 

HH 

hJ 

CD 


x 

O 


I 



















48 


Brakes in Freight Service 


note : 


INDIC^TEIS time: » Nl SECON ZDS. 



DOTTED " H s - - SLIDE 708 . 












































Brakes in Freight Service 


49 


NOTE: 

SC/^l_E INDICATES TIME! IN SECONDS. 



FULL LIME K - 
DOTTED” H ■ s - 


SLIDE 710. 





























50 


Brakes in Freight Service 


Slide 825 is similar to the preceding, except that the cards were 
made from the quick service triple valves. These curves show that 
the effect of brake pipe volume, due to length of train at the time of 
application, is less than with the old type of valve. 

Slide 707 illustrates the difference in time and pressure in the 
application of the brakes on the 1st, 25th and 50th cars. Not only 
is the rise of cylinder pressure shown, but also the rate of fall in 
brake pipe pressure, which will seem to be very slow on a train of 
even this length. 

Slide 709 is similar to the above, except that a 10-pound reduc¬ 
tion was made and consequently the differences in the results are 
more pronounced, both as between the brakes on the different cars 
and between the two types of valves with which the two trains were 
equipped. 

Slide 711 is similar to the above—the difference resulting from a 
15-pound reduction having been made instead of 10 pounds. 

Slide 713 differs from the above because of a 20-pound reduction 
having been made instead of 15 pounds. This series makes quite 
clear how much more effective and controllable a brake becomes 
when the time required to obtain certain brake effectiveness from 
one end of the train to the other is reduced. 

Slide 598 illustrates graphically both differences in time of release 
between the 1st, 25th and 50th cars of a train and the action of the 
brakes in the release when the retarded release type of triple valves 
is employed. It will be seen from the lower of the two sets of cylin¬ 
der cards that the first brake was released in .6 of a second and was 
entirely off when the 25th brake commenced to release, which was 
about 3^ seconds later and that the 25th brake was off before the 
50th commenced to release, which was about 4 seconds behind the 
25th. It will thus be seen that there is an interval of about 9 
seconds between the release of the 1st brake and the 50th and that 
the difference in the release of brakes between the 25th and 50th is 
4 seconds—time enough for the retardation still going on at the 
rear to do considerable damage if the slack runs out. 

From the upper set of cylinder cards, it will be seen that while the 
brakes commence to release with about the same difference in time 
that the release as a whole is very much more uniform—the effect 
being to eliminate surges in the train, due to brake release; thus 
doing away with a prolific source of damage and break-in-two. 


Brakes in Freight Service 


51 


Slide 708 illustrates the difference in time of release between the 
1st, 25th and 50th cars of a train, both as regards the different cars 
and two different types of valves. This and the cards shown on the 
following three figures are instructive also as illustrating the rate of 
rise of brake pipe pressure of a train of this length, namely, 50 cars. 

Slide 710 differs from the preceding in that it is a release after a 
10-pound reduction instead of a 5-pound. 

Slide 712 illustrates the difference in time of commencement of 
release of the brake and fall of cylinder pressure on the cars after 
a 15-pound reduction. 

Slide 714. The cards of this figure are taken from a 20-pound re¬ 
duction and illustrate the rate of rise of brake pipe pressure between 
the different cars of the train, the amount of cylinder pressure ob¬ 
tained, the time of release between the different cars, and the differ¬ 
ence in the rate of release of cylinder pressure between the different 
cars of the train and between the different types of valves. For 
example, with the old type of valve, the pressure was all out of the 
cylinder of the first car 3 seconds before the brake of the last car com¬ 
menced to release; while with the new type of valve, there was 25 
pounds in the cylinder of the first car when the brake of the last or 
50th car commenced to release and about 10 pounds in the cylinder 
of the first car when the effective pressure was out of the cylinder of 
the last car. In other words, the brake of the last car was released 
before that of the first car; thus the difference in time due to length 
of train was practically eliminated. The great value of this can 
only be appreciated by those who know the effects of having the 
rear end of the train anchored while the front end is running free. 

Whatever difference in cylinder pressure there appears on the dif¬ 
ferent sets of charts above mentioned has been due to the influence 
of the time factor as the piston travel was uniform. In the figures 
that follow the difference in cylinder pressure that appears is due to 
variation of piston travel, that is, increase or decrease of brake piston 
movement, which by the grace of somebody may exist before the 
shoes bear on the wheels. 

Slide 774. The significance of the curves of this chart is pointed 
out on page 146 of the paper. A prolonged study of this chart will 
cause considerable reflection, if nothing more concrete, and perhaps 
some may even ask these questions—how did we ever permit such 
conditions to come into existence, and why do we permit them to 
continue ? 


52 


Brakes in Freight Service 




47SEGrr 





1ST CAR 3 RAKE CYLINDER CARD. 


L 1 . , , . 1 


3-0 

i 1 a - A—J i I I I i 1 


in 



2Sta- CAR BRAKE Rlf»EL CARD. 



so 

X 


40 


25 T -? CAR BRAKE. CYLINDER CARO 


3-0 


SOIfl- CAR BRAKE PI PE CARO. 


So 30 -4 o 

—I I I I 1—1 I—1 1 l.il l I I I l 1 1 ) I I I I 1 I i I 


SOIfl- CAR. BRAKE CYLINDER CARD 


SLIDE 712. 



































Brakes ix Freight Service 


53 


NOTE 

INDICATES T i MEL INI SECONDS. 





3QTTE.D * H* —- SLIDE I 14 . 













































54 


Brakes in Freight Service 


Slide 254. This chart is very instructive as illustrating how the 
braking power may vary, due to no other cause than lack of piston 
travel maintenance. As the chart is largely self-explanatory, it 
will be sufficient to point out that the air stored in the auxiliary 
reservoir at 70 pounds may equalize into the brake cylinder at any 
pressure from 67 pounds down to 44 pounds contingent only upon 
difference in piston travel. But as the damage is done long before 
equalization of pressure is reached, we would show what results 


CHART SHOWING THE DIFFERENCE IN BRAKING POWER ON 
LOADED AND EMPTY CARS WITH ANY GIVEN BRAKE PIPE REDUC- 
TION.VARYING PISTON TRAVEL AND BOTH 70 AND 85 PER CENT 
BRAKING POWER BASED ON 60 LBS. CYLINDER PRESSURE. 

■ C r«OM * TO 3 POUND* LOWER THAN SHOWN ON CHANT, Out TO LEAKAGE,ETC. 



SLIDE 774. 


from a 10-pound reduction, which is the critical one of an applica¬ 
tion. Here we see the pressure obtained from a 10-pound reduction 
may vary from 60 pounds with 3" piston travel to only 12 pounds 
with 12 " piston travel, and what is worse in its effect in producing 
shocks that 60 pounds is obtained in the same time as the 12 pounds. 
Of course, there may be any of the variations between these two 
extremes. Now what does the engineer have to do with this, or 
how is he to prevent the results? Every car man and inspector 



































































Brakes in Freight Service 


55 


Moixvznvnoa aonaoad ox woixonaaa d a 



SLIDE 254. 


EFFECT OF PISTON TRAVEL ON BRAKE. 
CYLINDER PRESSURE OBTAINED FOR 10 LB. 
REDUCTION AND ON EQUALIZATION. 
















































56 Brakes in Freight Service 



slide 852 . 





























































































Brakes in Freight Service 


57 



&• ZO 2S 30 3S 

brake pipe rlduc non - pounps 

















































































































































































































58 


Brakes in Freight Service 


should be drilled until he knows by heart what produces these 
curves and what their effects may be. 

Slide 852. This chart carries the investigation of the effect of 
varying piston travel further, in that we are able to see what it 
means in the braking power on the car and from this infer what 
such un-uniformity may mean to the train as a whole, particularly 
if we figure the various combinations and distribution that may 
occur. It will be seen that with the braking power designed for 
70% of the light weight of the car a 10-pound reduction will result 
in about 9 pounds cylinder pressure and about 10% braking power 
on the car with long piston travel; while on the car with short piston 
travel for the same reduction and in the same time the cylinder pres¬ 
sure will be 32 pounds and the braking power 35%. A further in¬ 
vestigation of the curves will disclose a multitude of possible varia¬ 
tions which, fortunately, may be held down to very narrow extremes 
by very little care, which, however, must be given before the train 
leaves the terminal, as the engineer is not furnished with any mechan¬ 
ism that will compensate for improper conditions of brake equip¬ 
ment, nor can he expect except in rare instances to avoid the con¬ 
sequences. 

Slide 853 is a different method of illustrating this matter, but more 
graphically develops the comparatively slight differences in the 
equalized pressures and the great differences for partial applica¬ 
tions for the same difference in piston travel. Also that the very 
high cylinder pressure resulting from short piston travel is obtained 
with less than half the reduction and in less than half the time that 
the equalized and lower pressure is obtained with the long travel. 
Plainly, few know that these things exist or few care—either horn 
of the dilemma is not comfortable and I may say neither is profit¬ 
able. Fortunately the most extreme neglect will not destroy the brake 
as an emergency safety device, but considerable care is required to re¬ 
tain its efficiency as a service brake , and this is all the more important , 
as serious losses may otherwise result. In other words, as with any¬ 
thing less mechanical, certain physical conditions must exist if we 
are to obtain profitable and desired instead of unprofitable and un¬ 
desired results. It would not be necessary to mention this if we 
were speaking of anything else but the air brake. 

Slide 854 still further illustrates piston travel effects, it being hoped 
by the number and graphicness of the illustrations that some sort 
of notice will be taken of the importance of this element in its effect 


to is 20 as 

Brake Pipe. PEDucnon — Pounce 


Brakes in Freight Service 


59 



SLIDE 854 . 















































































































































































60 


Brakes in Freight Service 


on train control. In this chart, the variation of both pressure and 
difference in percentage of braking power that may occur, either 
side of that desired in the design is shown. 

Figures 853 and 854 are analyzed on page 147 of the paper to 
some extent, to which the reader is referred. It is hoped that some¬ 
thing has been said on this part of the subject which will impress 
upon all concerned the necessity of giving it the consideration that 
results in some action being taken. 

Slide 855. This chart illustrates graphically the movement of 
the air and the action of the brakes both when the brake valve is 
manipulated, in releasing the brakes of a 75-car train, as it should 
be and as it should not be. Curve 1 proves how serious the improper 
manner of releasing the brakes may be—the result being “stuck 
brakes” and undesired quick action on the next application. The 
curves of this and the following figure are interesting and instructive 
in showing how the pressure rises and falls in different parts of the 
train and that the time interval between the action of the brake first 
and last is a factor to be reckoned with. 

From a train operating standpoint, the curves shown on this chart 
are perhaps the most important ever recorded, for an inspection of 
those curves showing improper operation will demonstrate that a 
great many troubles and losses with the brake are due entirely to 
the improper use of the full release position. One reason for calling 
attention to these particularly is that all the evils resultant from 
such manipulation can be avoided without the expenditure of a 
dollar for apparatus or repairs. It will be seen from curves 1 and 
3 that overcharging, stuck brakes, undesired quick action are the 
resultant of such improper methods of manipulation. It almost 
seems needless to say that in a train with this we have flat 
wheels, cracked wheels, broken wheels, buckling of trains, and 
break-in-twos, as well as a great number of happenings of lesser 
significance. 

Another thing, however, should be pointed out, namely, that such 
methods in grade work result in the forward brakes of the train 
doing practically all the work of controlling the train, which viewed 
from any standpoint is bad. 

Curves 2 and 4. (Slide 855). It will be seen that none of these, 
things result when the proper method is employed. In fact, just 
the contrary for the operation of the brakes is then all that can be 


Brakes in Freight Service 


61 


desired as far as brake valve control is concerned. A note on each 
curve briefly gives the operation and result, but an individual 
analysis of each of the curves cannot fail to convince all concerned 
that there are some things to avoid when operating the brakes. 

Slide 856 to 859 and 860 and 861 inclusive are intended to show 
the difference in time in the release of the brakes when using run¬ 
ning position with a 30-car train and full release position with an 
80-car train after both a 10 and 20-pound reduction. These curves 
also show that the rise of pressure is much more rapid with the brake 
valve in running position for a 30-car train than in full release posi¬ 
tion for an 80-car train. In fact, these charts were made to demon¬ 
strate, to some who doubted, that the brake which will release when 
full release position is used on an 80-car train is even more certain 
to release in a 30-car train if only running position is used. 

Another point worthy of notice is that some of the brakes on the 
80-car train had not released by the time the brake valve handle was 
returning to running position, consequently, they were released 
from running position. The vertical lines show when the triple 
valve went to release position, as at this point the indicator was 
closed and opened again quickly. Some of the lessons to be learned 
from these four charts are, if the brake valve handle is held in re¬ 
lease position long enough to insure that all brakes are released while 
the handle is in this position, that the head end of the train will be 
overcharged, that the time of the release of the brake depends more 
upon the length of the train than the position of the brake valve 
handle and that the rise of brake pipe pressure when releasing the 
brakes, like the fall of pressure when applying the brakes, is also 
dependent more upon the length of the train than upon the posi¬ 
tion of the brake valve, and finally that the interval between the 
release of the first brake and the last is dependent upon the length 
of train. Of course,- these differences both in application and re¬ 
lease are very much reduced and greater uniformity secured by the 
later type of triple valve, but even with these better results will be 
obtained if it is understood that different conditions involve dif¬ 
ferent results unless the manipulation be modified accordingly. 

Slides 860 and 861. These charts are similar to those prece ling, 
except that the brake pipe pressure has been reduced below the 
equalizing point. This is an operation that is very likely to be pro¬ 
lific of damage, particularly break-in-twos, as it is not difficult to 


62 


Brakes in Freight Service 



slide 856 . 










































Brakes in Freight Service 


63 


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64 


Brakes in Freight Service 



slide 858 . 



















































Brakes in Freight Service 


65 



























































66 


Brakes in Freight Service 



slide 860. 















































MOUEMENT or BROKE UflLUE 



T^r>E IN seconds^ 75 so g 3o s ioc 105 WO I IS \2.o 

1 I Ti i i i I 1 II I 1 I LI i I I i I I li l l l I i l l i I I I I I -Lj—1 J 1 I I 1 1 1 I I I I I I I I I 1 1-L 


BRflKE-PlPE PRESSURE -SOtHCrR. 
flUXILIBRV RESERUO l R PRESSURE ■ So... CHK; 



50 CAR TRAIN. 15 LB. BRAKE PIPE REDUCTION — ALL BRAKES 
APPLIED. BRAKE VALVE HANDLE PLACED IN FULL RELEASE POSITION 
FOR 30 SECONDS; BRAKES FROM I TO 14, INCLUSIVE, AND 17 RE-APPLIED, 
DUE TO OVER-CHARGING, AND REMAINED APPLIED. BRAKE VALVE 
HANDLE WAS THEN PLACED IN RUNNING POSITION FOR 15 SECONDS 
FOLLOWED BY A 10 LB. BRAKE PIPE REDUCTION - ALL BRAKES APPLIEJD, 
BUT WITH 52 LBS. ON HEAD END AND ONLY 5 LBS. ON REAR. 




6RRKE CXLINOER 


BROKE “PIPE PRESSURE - Is 


•flux l LIF1 R. Y RESERUO 1R PRESSUf 


PRESSURE. - 1ST COR. 

i CYLINDER PRESSURE -SOTrCRR. 


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Curve j. 



BRftKE - Pi PE PRESSURE - S O CPU, 
flUXIURRY RESERUOtR PRESSURE -SO T .Cf\R, 


50 CAR TRAIN. 15 LB. BRAKE PIPE REDUCTION — ALL BRAKES 
APPLIED. BRAKE VALVE HANDLE PLACED IN FULL RELEASE POSITION 
FOR 10 SECONDS; BRAKES I AND 2 RE-APPLIED, DUE TO OVER-CHARGING. 
BRAKE VALVE HANDLE WAS THEN PLACED IN RUNNING POSITION FOR 
35 SECONDS FOLLOWED BY A 10 LB. BRAKE PIPE REDUCTION; ALL 
BRAKES APPLIED, AND WITH PROPER UNIFORMITY. 



BROKE CrUNbER PR 

-- 


J 

<0 



PE PRESSURE 

s' 


JRE -1st C-RR UX1L1P1RY RESERUOlR PRESSURE -IstCRR, 


BROKE CruiNOER PRESSURE - 50 tm C.RR 


ifl 

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ULS 130 I 

I I I I I I l I I I I I I 


Curve 4 . 
Slide 855. 











































































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Curve 2. 
Slide 855 . 













































































































Brakes in Freight Service 


6 



slide 861 . 

















































68 


Brakes in Freight Service 


raise the brake pipe pressure up to that of the auxiliary reservoirs 
at the head end of the train, but it is impossible to raise the brake 
pipe pressure at anywhere near the same rate at the rear of the train, 
consequently, there is much greater interval of time between the 
release of the forward brakes and the rear brakes than where the 
brake pipe pressure has not been reduced below that of the auxiliary 
reservoir. In fact, so long as an interval exists that the engineer 
is very likely to help the retardation still going on on the rear, break 
the train in two by opening the throttle, if the train is still running 
and, if standing, by starting the forward end of the train before the 
brakes have released at the rear. After the brake pipe pressure 
has by any means fallen below that of the auxiliary reservoir a very 
long period of time, comparatively, must elapse before the brakes 
will release at the rear end of the train. This is apparent from an 
inspection of the rate of rise of brake pipe pressure, as show on the 
charts, which is not more than 8 pounds per minute after the for¬ 
ward triple valves have gone to release position; consequently, 
if the brake pipe has been reduced 10 pounbs below that of the 
auxiliary reservoir about 1 minute must elapse before it is certain 
that the brakes have released. 

A glance at Slide 861 will show that after such an over reduction 
that part of the train ahead of the 25th car was running free before 
even the 50th car had started to release. 

Mr. Turner, Answer No. 1: Replying to the first question asked 
by Mr. Symons, I may say that the great differences in braking 
power may come from each or a combination of several causes, 
namely : difference between empty and loaded weight of cars, differ¬ 
ent standards of braking power on different railroads, and some¬ 
times even by the same railroads, variations in piston travel, brake 
cylinder leakage, length of train, and the use of different makes of 
brakes, in which the auxiliary reservoir and brake cylinder propor¬ 
tions are different and in some of which the service amd emergency 
brake cylinder pressures are the same. All of these factors are dealt 
with at considerable length in the body of the paper and various 
suggestions as to their elimination in some cases and a minimizing 
of their detrimental effects in others are given, and finally it is 
stated that the officials have the choice of correcting some of these 
evils as they do others in connection with railroad management, or 
of letting them exist, which, however, will not be done when it is 


Brakes in Freight Service 


69 


realized how profitable an air brake in good working order may be 
made, particularly as this will eliminate from the loss side of the 
account the cause of troubles and damage always inseparable from 
mechanical devices not in proper working order. I respectfully 
refer those who require a more complete answer to Mr. Symons’ 
question to those pages of the paper covering this subject and to the 
curves and charts in the appendix. 

Answer No. 2 : In many cases the variation in cylinder pressure 
on different cars, or on the same car at different times, for the same 
amount of brake pipe reduction is due to improper foundation brake 
gear design, making it impossible to obtain or maintain the piston 
travel required by the auxiliary reservoir volume (which, it may be 
needless to say, is the same for all brake cylinders of the same diam¬ 
eter in steam railroad practice), which necessarily means that the 
stroke of the piston must be uniform if the same and proper cylinder 
pressure is to be obtained. In this connection I may say that very 
few designs for foundation brake gear are furnished by the Westing- 
house Air Brake Company—in many cases the general practice being 
to build the car without any particular reference to the foundation 
brake gear and then put it on as may best or easiest be done, nor 
was this so important when the brake was looked upon as a mere 
safety device, but since it (the brake) is now essential to control 
trains in ordinary every day operation, it is also essential that 
greater consideration be given to foundation brake gear design, 
installation and general maintenance. However, the chief causes 
of differences in cylinder pressure are neglect to adjust piston travel 
for brake shoe wear and the hanging of the brake beams on the car 
body side of the springs, which permits the piston travel to change 
according to whether the car is empty or loaded, and also very 
materially increases the piston travel by the creeping of the shoes 
toward the rail when the brakes are applied, due to pull of the wheel 
on the shoe. This latter is one of the worst forms of false travel. 
This question is also covered more in detail in the text of the paper 
and by the curves and charts. 

Answer No. 3: As it was not the purpose of the writer of the 
paper to go quite so far as we are carried by this question, an answer 
is not exactly called for, still I might be pardoned for saying that in- 
ferentially this bears out the statements made in the answer to Ques¬ 
tion No. 2, that foundation brake gear designs are sometimes bad. 


70 


Brakes in Freight Service 


Another reason for not answering this question is that the answer 
is contained in the question, for Mr. Symons has so well outlined the 
stresses set up by such an installation that there can be no doubt of 
the bad effect of such a design of the brake, or that, under certain 
conditions, the tendency is to. derail the car. 

Answer No. 4: The writer mentioned draft gear in one paragraph 
of the paper and then only to call attention to the fact that in some 
cases the cause of a break-in-two could be found in the draft gear, 
and, wherever the draft gear is too weak for the stresses to which 
it may be subjected, or is weakened by usage, it is -likely to give 
way under conditions where it would not occur if of proper strength 
or design. Moreover, break-in-twos often occur where a draft gear 
is employed that absorbs energy instead of dissipating it, as is the 
case with spring gear, and this will be all the more appreciated when 
it is considered that the recoil is given back in the form of a jerk 
instead of a buff—a jerk being much more likely to part a train 
than a buff. 

As the draft gear situation is before us in many papers, pamphlets 
and discussions, the writer thought it was sufficient to merely call 
attention to draft gear as one of the elements involved in the general 
question, and, therefore, to avoid repetition respectfully refers 
those interested to literature dealing with draft gear problems and 
designs. 

As to sending cars to the repair track I may say that nine-tenths 
of the work required to eliminate air brake troubles and obtain 
proper efficiency can be done without sending cars to the repair 
shop. Instructions to inspectors and carmen as to what to do in the 
way of stopping brake pipe, brake cylinder and retaining valve 
leaks and adjusting piston travel and insistence upon its being done 
is one of the chief requirements, and all this work can be done with 
the train in the'yard. True, it will take some little time, but the 
delays will be nothing compared with those how occurring on the 
road and, of course, the damage to equipment and lading will be 
eliminated proportionately. Next, engineers should be taught 
that there is some difference between handling a long train with all 
the brakes cut in and a short train; also a difference in handling 
all empties, all loads or mixed trains; also that conditions are differ¬ 
ent now that we have “all air” trains that when only the brakes 
on a few cars were used and the remainder not. In fact, the mani- 


Brakes in Freight Service 


71 


pulation required now, in many instances, is the reverse of what it 
used to be. For example, the old rule was to bunch the slack before 
applying the brakes—the present rule is to avoid this. Again, with 
small pumps and small main reservoirs and low pressures, the full 
release position could be used with impunity, but with large com¬ 
pressors, large main reservoirs and the high pressures of today 
(which have a reason for their existence), the full release position 
must be handled with considerable thought of the consequences. 

Again, with the brakes used only on a few cars, and these loads, 
and the slack of the cars behind the air cars bunched by use of 
straight air on the engine, or other means, a heavy reduction was 
not only permissible, but proper, but now with the air operative 
throughout the train and empties behind, a heavy reduction is 
likely to break the train in two, because of the disparity in retarding 
force between the loaded and empty cars. In other words, the 
initial reduction now made should be light in order that the cylinder 
pressure obtained on the empty cars should not create such retarda¬ 
tion at the rear as would break the train in two. It will be seen 
that none of these things involve sending cars to the “rip” track. 
Of course, there are some cases where this is necessary and it should 
be done, but this is not so universally necessary as is generally 
thought. In fact, I believe it is the impression that this is neces¬ 
sary which is responsible for the failure to make the slight repairs 
and compensations required for wear and tear between terminals. 
The defects are generally small individually, but the potentiality 
for trouble in an aggregation of these is great. We are not limited 
to two horns of the dilemma as implied in the interrogation of 
whether or not we shall send cars to the “rip” track, for it is not 
a question whether we send all or none, as we may send only those 
that require such repairs as cannot rapidly and quickly be made in 
the yard, repairing such others where they stand. 

In conclusion, I may say that it was not the writer’s intention to 
usurp the prerogative of the railroad official and say what can or what 
cannot be done, nor how things should be done, but to point out 
what is required to efficiently control freight trains and what is 
response for failure to get such control—the pleasure of devising 
the means and method being left to those concerned, as well as the 
choice of having things as they are, or as they ought to be. 

Pub. 573-2 
3m 














































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One copy del. to Cat. Div. 


tft M H2 1816 



LIBRARY OF CONGRESS 


0 033 266 406 2 


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